Another Zenith question...

Gary71 · Post by **Gary71** » Sat Dec 04, 2004 2:15 pm

Does anyone have experience of removing the overrun enrichment circuit on the Zenith 40TINS? Good/bad? More overrun popping due to lean mixture?

My solenoid is missing (and supposedly difficult to get hold of).... and I'm not too fussed about hydrocarbons on overrun. Adding more fuel/air to reduce emmisions seems a waste of fuel.

This is whats left of the control diaphragm...

I'm considering blanking the whole thing off. Looking at the cross section drawings it shouldn't affect anything else if properly sealed.

Any thoughts would be appreciated.

Barry · Post by **Barry** » Sat Dec 04, 2004 5:33 pm

Gary, I've got mine disconnected, as there was no feed coming from the engine speed sensor anyway: all seems to be fine, no popping on the over-run, idles fine, and does everything you would expect when the throttle is 'blipped'. I also saw another 911T with Zeniths at the technical symposium, and that was simply disconnected as well. I'd blank it: build in some simplicity!

Gary71 · Post by **Gary71** » Sat Dec 04, 2004 6:24 pm

Sounds like the way forward, particularly as it means I don't have to try finding a solenoid

At least I've discovered what that random wire in the valley plate does! (or rather doesn't...)

Did you just plug the cylinder feed pipes then wind the flow rate and mixture adjusting adjusting screws all the way in? Should do the trick I think. Solenoid hole is already plugged.

Rather tempted by your MSD ignition set up...I could try convincing the wife to get it as a Xmas pressy!

Gary71 · Post by **Gary71** » Sat Dec 04, 2004 11:25 pm

Brave pill has been taken so went for tapping the carb bodies to except some 'plugs'.....

Cut and shut M8 cap head in the flow adjuster hole and some M5 screws in the cylinder feed pipes. Flow adjuster hole took an M8 tap perfectly, the feed pipes had to be drilled out, they were just slightly too large for M4 screws which was the first attempt. M5 cap heads would be neater but these screws will have to do for now. With the mixture screw done up tight the system should be sealed off. Second opinions welcome!

Nearly finished one!!! How long a job is this

Second one should be quicker I guess...